Field of the Invention
The present invention relates to a control device, an optical apparatus, an imaging apparatus, and a control method.
Description of the Related Art
In imaging apparatuses such as digital cameras, important works for imaging, such as exposure decision or focus manipulations, are fully automated. In imaging apparatuses on which anti-vibration control devices preventing image blur caused due to camera shake or the like are mounted, factors causing mistakes in photographing by photographers are mostly resolved.
However, photographing in a state such that subjects are moving or photographing in telephoto states such that a focal distance becomes large causes following problems. When a subject is moving and deviates from a photographed image, it is necessary for photographers to perform special techniques in order to track the continuously moving subject by performing manipulations with high precision. When photographing is performed with cameras including telephoto lenses with greater focal distances, influences of image blur caused due to camera shake increase. Therefore, it is difficult to maintain main subject at the center of the photographed image. Even when the photographer manipulates imaging apparatuses to get the subject back inside the photographed image, the imaging apparatus performs blur correction on camera shake amounts due to intentional manipulations by the photographer. Therefore, it is difficult to minutely adjust the subject inside the photographed image or at the center of the photographed image due to the influence of anti-vibration control.
Japanese Patent Laid-Open No. 2010-93362 discloses an imaging apparatus that automatically tracks a subject by moving a part of an optical system in a direction intersecting an optical axis. Japanese Patent Laid-Open No. H7-226873 discloses an imaging apparatus that extracts a target subject from a photographing signal to output the position of the center of gravity of the subject and tracks a subject using a rotary camera platform or the like so that the position of the censer of gravity of the subject is output in the vicinity of the center of a photographed image.
When subject tracking is performed so that the central position of a subject is maintained at a specific position of a photographed image in the imaging apparatus disclosed in Japanese Patent Laid-Open No. H7-226873, delay or precision of subject detection may have an influence on tracking control. In addition to time wasted in the delay of detection of the subject, the imaging apparatus has to perform feedback control to maintain a subject in the vicinity of a specific position of a photographed image. When a feedback gain is increased to raise a subject tracking property, the imaging apparatus may perform oscillation depending on a photographing condition. When the feedback gain is decreased so that the oscillation is not performed, the subject tracking property is lowered and it is easy to miss a subject in a photographed image.